1. Field of the Invention
The present invention generally relates to a complex circuit board and a fabrication method thereof, particularly to a technology of combining circuit boards using corresponding fixing structures thereof to form the complex circuit board without extra attachment units.
2. Description of the Prior Art
Various display electronic products have been developed in recent years. Among various types of flat displays, liquid crystal displays (LCD) have become the mainstream products, for example, LCD TVs and computer LCD monitors.
FIG. 1 is a schematic view of a conventional liquid crystal apparatus. A display apparatus 1 has a display panel 100 and a backlight module 200. The backlight module 200 has a light-emitting device 210. The light-emitting device 210 supplies backlight for the display panel 100. Therefore the display apparatus 1 displays full color image for viewers.
FIG. 2A is a schematic view of the light-emitting device 210. The light-emitting device 210 has light sources 212 and circuit boards 214. The circuit boards 214 transmit signals to the light sources 212 to control the power or the brightness of light sources 212. Light emitting diodes (LEDs) could be used as the light sources 212. The circuit boards 214 include a printed circuit board assembly (PCBA) 216 and a flexible printed circuit (FPC) 218 combined with each other. The printed circuit board assembly 216 has a supporting surface 215 and the light sources 212 are disposed on the supporting surface 215. The printed circuit board assembly 216 has a combining section 217 for attaching a bend portion of the flexible printed circuit 218 onto the printed circuit board assembly 216 and electrically transmitting driving signals of light sources.
FIG. 2B illustrates a combining method for the circuit boards 214 of the conventional display apparatus 1. The flexible printed circuit 218 is bent and attached onto the printed circuit board assembly 216, wherein attachment units 219 (e.g. tapes) are attached onto the combining section 217, thereby strengthening the pull strength of flexible printed circuit 218 and reducing the possibility of poor signal transmission induced by the stress acting on the combining section 217. However, the above combining method needs additional processes for attaching the attachment units 219 to strengthen the combining portion 217. Furthermore, the ability of the attachment units 219 in strengthening the pull strength of the combining section 217 is limited. For large-size display application, the combining strength of circuit boards 214 should be further improved.